Senate Majority Leader Bill First (search) will officially call up the nomination of Priscilla Owen (search) to be an appellate judge for the 5th Circuit Court of Appeals on Wednesday ay 9:30 a.m. EDT, a senior GOP Senate aide said, setting up the possibility that the Senate could face a showdown on judicial filibusters sometime next week.

On Thursday or Friday, Frist will file a "cloture" petition to end the debate and move to a vote for Owen. Due to procedural rules, the Senate can't vote on cloture until one whole day has passed, which puts a vote on cloture into next Monday or Tuesday.

A vote on cloture is not the vote to change the rules on banning judicial filibusters. It is a test vote to show support for cutting off debate on Owen's nomination and requires 60 votes to succeed and prevent a filibuster.

If the GOP loses the cloture vote, Frist will turn to the Democrat-named "nuclear option" — or what Republicans call a "constitutional option." That vote could happen around Wednesday but also could be pushed back as far as Monday.

The nuclear/constitutional option is not a vote to confirm Owen. It is a vote to change the precedent by which the Senate considers Circuit and Supreme Court nominees.

Frist will not call up the nomination of Janice Rogers Brown (search), a California Supreme Court justice nominated to the Circuit Court of Appeals for the District of Columbia, on Thursday. Although Brown's nomination likely will be talking about during the Owen debate, the Senate will only vote on Owen next week.

In order to allow the vote on the nuclear option, Frist must ask the presiding officer in the Senate — anticipated to be Vice President Dick Cheney (search), who is the Senate president — for a "point of order." In other words, he would ask Cheney to determine a "fair" amount of time to allot to debating Circuit Court and Supreme Court nominees before permitting a vote on the confirmation of nominees.

Cheney would then rule on the amount of "fair" time for debate before taking a vote on whether to confirm nominees. At this point, a Democrat, most likely Minority Leader Harry Reid (search), would appeal Cheney's ruling.

Frist would then move to "table," or effectively kill, Reid's appeal. A motion to table an appeal is not debatable, meaning that this would be the nuclear/constitutional vote and requires only a simple majority to succeed.

If the chamber splits on the vote, Cheney would be the tiebreaker and would be expected to vote to kill Reid's appeal, meaning his determination of fair time for debate would stand and the precedent would be changed.

At that point, the new precedent would be established and all future judicial nominees would only need 51 votes to be confirmed. If the GOP wins the precedent change, then Frist can order a vote on Owen's nomination. She is believed to have enough support to win 51 votes for confirmation.

The senior GOP aide said that between the time the Senate would vote in favor of changing the precedent and when senators actually take an up-or-down vote on Owen, Democrats would have the opportunity to "make mischief." The aide said the GOP expects the Democrats to do so but that ultimately and eventually — likely before the Memorial Day holiday — Owen will get her confirmation vote.